1. Field of the Invention
The present invention relates to a new class of compounds identified as overbased metallic compounds of polyarylamine sulfides and polyarylamine-phenol sulfides. It further relates to improved lubricant compositions. More particularly, it relates to lubricants which have been improved by the addition thereto of one or more of said overbased compounds.
2. Discussion of the Prior Art
It is well known that many organic liquids and solids used in industrial fluids, such as oils and greases, power transmission fluids and the like, may deteriorate and lose their ability to function when subjected to oxidation. Since these substances are very often used at high temperatures, the rate of oxidation breakdown can be very rapid. This problem is particularly important in the operation of present day automotive and aircraft engines.
The breakdown of lubricant is almost always accompanied by the formation of sludge, corrosive acids and other products. These can harm the metal surfaces of engines or other machines and interfere with efficient operation of the lubricant.
No art is known which discloses the overbased compounds taught herein. There are numerous other compounds, however, taught in the art which impart property improvement to lubricants in combination therewith. For instance, U.S. Pat. Nos. 3,156,728 and 3,224,972 teach 4,4-thiobis[2,6-di(lower alkyl)aniline] compounds for the purpose of imparting antioxidant properties to organic compositions therewith. Further, U.S. Pat. No. 2,848,444 teaches lubricant compositions containing a reaction product of a metal polysulfide and diphenylamine, or an alkyl derivative thereof, having improved oxidation and corrosion properties. U.S. Pat. No. 3,217,038 teaches the use of an alkylthioalkyl diaminodiphenylalkane for the purpose of imparting stabilization to an organic substance by mixture therewith. Also, U.S. Pat. No. 3,347,792 teaches lubricant compositions containing a reaction product of (1) ammonia, a primary amine or a secondary amine with (2) carbon disulfide and (3) an aliphatic epoxide.
U.S. Pat. No. 3,844,956 relates to improving lubricants by adding thereto an amount of an amino-substituted polyphenylthioether, an intermediate compound in the manufacture of the compounds of the present invention.